Drafting instrument.



No. 874,384. PATENTED DEG. 24, 1907. J. H. BLAIR.

' DRAPTING INSTRUMENT.

APPLICATION FILED JNE 26, 1907.

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. No. 874,384. u PATBNTED DEG. 24, 1907.

I J. H. BLAIR. l DRAFTING INSTRUMENT. APPLICATION FILED TUNE 26. 1907.*

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lJOSEPH I-I. BLAIR, OF BOWLING GREEN, MISSOURI.

DRAFTING INSTRUMENT.

Specification of Letters Patent.'

Patented Dee 24,1907.

Anplieation filed June 26, 1907. Serial No. 380,949.

To all whom it may concern:

Be it known that I, JOSEPH H. BLAIR, a citizen of the United States, residing at Bowling Green, in the county of Pike and State of Missouri, have invented a new and useful Drafting Instrument, of which the following is a specification.

My invention relates to improvements in drafting instruments, and the objects of my improvements are to provide a single instrument to draw outlines, plans, charts, diagrams, plots and geometrical figures; and to measure angles, distances, elevations, depressions and areas, which ordinarily require the use of the traverse tables and the following instruments, viz-drawing-board, T square, graduated rule, dividers, compass, parallel rules, triangle,'protractor and drawpen. I attain these objects by the mechanism illustrated in the accompanying drawing, in which- Figure 1 is a top plan view of the entire instrument; Fig. 2 is a top plan view of the base, the disk removed: Iig. 3 is a central vertical sectional view of the instrument; Fig. 4 is an enlarged view of the rule and support with part in section; includinglig. 5 Fig. 6 is an enlarged view of the stop and Vernier for disk; Fig. 7 is a detailed perspective view of pen and pencil holder, and Fig. 8 is a detailed perspective view of drawing-board and slides.

Similar figures refer to similar parts throughout the several views.

The instrument consists of:

1st. A base, Iig. 2, with polygonal sides and mounted on legs 10 10 10 10, having, a central circular plate with a central cylindrical projection 13 on its upper surface and a circular vertical orifice 14 through its center, and a circular rim projection 12 on its outer and upper surface, the outer edge of the rim projection coinciding with the outer edge of the plate, horizontal ribs 9 9 9 9 9 9 9 9 extending from the outer edge of the plate and attaching to the sides of the base at its angles, the upper surface of the projections 12 and 13 lying in the same plane and the upper surface of the body of the plate, the ribs and sides of the base lying in the same plane, two horizontal arms 11 11, oppositely extended from the upper portion of the sides of the base, their longitudinal center in line with the axis of the base, and each having a rectangular orifice 19 19 near its outer end to receive the lower shouldered end of the support 17 Iiig'. 5, and also an inner rectangular orifice 21 21, to receive the lower shouldered ends of the verniers, shown in Fig. 6, said vernier attachments and supports being retained in said orifices by set-screws.

2nd. A disk,l ig. 1, centrally and rotatably mounted on the base, consisting, of a central circular plate with a rim projection and a central cylindrical projection on its under surface, of the same periphery and coinciding with the similar projections 12 and 13 of the base, the cylindrical projection having a shaft centrally iixed therein a-nd extending vertically downward and adapted to operate in the circular orice 14 of the base, horizontal ribs, similar but longer than those of the base, extending from the edge of the plate and attaching to an outer circular rim 15, on the outer and'upper surface of which is inscribed a compass circle, figured each way from 0 to 90o from the north and south points, the upper surface of the plate, ribs and rim lying in the same plane, -but the under surface of the ribs slant upward and outward from the edge of the plate to the rim in order to avoid contact with the base when the disk is rotated.

3rd. A drawing-board, Fig. 8, comprising, a rectangular frame, and two end bars 42 42 extending across the face of the disk from rim to rim and fixed thereto by means of screws, and a slide 39, operatively fixed in the upper portion of the sides 4 0 4() of the frame, by means of a tongue on each edge of the slide and a longitudinal slot 43 in each side of the frame. The frame is slidably fixed into a longitudinal slot 44 by means of a tongue projection o'n the ends of the frame adapted to fit into said slot 44 of each end bar 42 42. Upon the upper surface of each side of the frame is inscribed a scale of linear measurement, its divisions corresponding with the divisions of the rule, shown in Figs. 5 and 6. The upper surface of the end bars 42 42 have inscribed on each a scale of linear measurement, its divisions corresponding with the divisions of said'rule, and graduated as desired. The ends of thev frame 41 41,

each have centrally inscribed upon their upper surface a Vernier 45 45, auxiliary to the scales on the end bars 42 42. The body of the slide is coextensive with the inner space of the frame, and has centrally xed on each side a vernier 46 46 which are auxiliary to the scales on the sides 4() 40 of the frame. The upper surface of the slide and sides of the frame lie in the same plane, and the upper surface of the end bars 42 42 and the ends 41 41 of the frame lie in the same plane, but on a plane slightly lower than the under surface of the slide in order to permit the operation of the slide over them. The purpose of said frame and its slide is to atl'ord a support for the drawing material, and to adjust each station or initial point, of a lin'e drawn, to the center of the disk directly under the point of the pen, and to get its bearing by means of the rule and compass circle of the disk, and from the side and end scales and 'their auxiliary verniers to find the latitude, departure and meridian distance of the line, data from which the area of a ligure may easily be computed without the aid of traverse tables.

4th. A rule, Fig. 5, rectangular in shape, and extending across and above the upper surface of the disk and along its axis, on each side of which is inscribed a scale of linear measurement, graduated as desired, its ends being adjustably attached to the upper ends of the vertical supports 17 17, by means of a transverse slot in the under surface of the rule near cach end, said slots having a tongue projection extending inward from the inner side of the slot, adapted to slide in a horizontal groove in the inner side of each vertical support and retained by set-screws 18 1S, the lower ends of said supports being shouldered and adapted to fit into the orifices 19 19 of the arms of the base and retained by set-screws entering therein from the ends of the arms.

5th. A drawing-pen attachment, Fig. 4, consisting of a rectangular slide 29, having, an inner rectangular and longitudinal opening throughout, to receive the rule on which it is intended to slide, a rectangular aperture in each side and extending to near its ends, the edges of the aperture slanting outward, and on the lower slant of each aperture is inscribed a vernier 47, auxiliary to the scales on the rule. Centrally mounted across the upper portion of the slide by means of screws entering the sides of the slide, is a device, its under surface elevated above the upper surface of the slide, and each end extended upward 30 30, and also downward and longitudinally along the upper portion of the slide, the ends of the longitudinal extensions slanting diagonally inward and outward, each downward vertical 'extension having a vertical slot extending from its lower edge, the

sides of slot slanting inward and outward from its inner edge in which the pen-holder 36, Fig. 7, is adapted to operate; each extended end having a shaft 31 31, its head projecting above the upper surface of the extension, operatively fixed in a circular vertical orifice and extending down into said slot and attaching to the upper end of the penholder 36, the lower end of the pen-holder having a vertical orifice adapted to receive the shaft of a drawing-pen 3S, which is retained by set-screws 37 37 entering the slots from the outer sides of the holders, the upper portion of the shafts are encircled by a spiral spring to hold the point of the pen above the drawing surface, and by depression to permit it to come in contact with it, having a stop 32, cylindrical in shape at the top and rectangular at the bottom, operatively inserted through a spiral spring and through the central cross portion of the device, and the rectan gular end extending down through the upper portion of the slide into a transverse groove 32 in the upper surface of the rule, located at a point thereon, where, when the stop enters it, it will lock the attachment, so that the point of the pen will stand directly over the center of the disk. The stop is actuated by a slide operating in an orifice in the upper portion of the rectangular portion of the stop, having its upper surface 33 slanting from near one end toward the other, with vertical posts 34 34 at the ends, said slide having a longitudinal slot through its horizontal portion to receive the vertical post 35 which is fixed in the central upper portion of the slide 29 and is a guide for the stop slide. The pen attachment is provided with two pen or pencil holders for the following purposes: 1st. To use different colored inks, without having to remove and clean the pen every time a different color is used. 2nd. A pen may be used in one and a pencil in the other. 3rd. Either pen may be set transversely to the rule to draw east and west, and circular lines from any point along the rule without adjusting the slide in the frame so as to have the initial points of the lines begin at the center of the rule. To use either pen only requires the shifting of the frame so as to bring that pen to the desired point on the drawing surface.

6th. Two vernier attachments, Fig. 6, each comprising, a vertical support 20, a hinged inner piece 22, to the upper and inner side of which is attached a horizontal bar 23, its inner surface being the arc of a circle of the same periphery as the outer edge of the disk, its upper surface lying in the same plane as the upper surface of the rim of the disk, and having a vernier inscribed thereon, graduated each way from or to a central division, and adjusted contiguously against the edge of the disk by means of a spiral spring encircling a pin 27 fixed in the vertical support and operating through the hinged inner piece 22. One of said attachments having a stop 25, attached to a lever 24, its lower end attached to the end of a screw 26 entering the outer side of the vertical support. The stop is adjusted to operate through an orifice in the vertical support, thence through a spiral spring, by which it is actuated, and through an orifice in the hinged 22 and vernier portions 23, and enter an orifice 28 in the edge of the disk 15, the vernier attachment being so located, that when the stop enters the orifice in the edge of the disk, it will lock the disk in a position, where the central divisions of the verniers 23 l23, the 0o points of the compass circle and the center of the disk will be in alinement.

The verniers, mentioned in these specifications, may be graduated to read their auxiliary scales to the 1 100 part, or more, of their finest divisions.

The drawing area of the instrument is dependent on the diameter of the disk and the distance of the vertical supports 17 17 from the center of the disk. The rim and cylindrical projections of the base and disk should be of such diameter as to secure easy and steady rotation of the disk, yet, so as to afford sufficient friction in the rotation of their coinciding surfaces, in connection with the pressure of the-stops 25 25 on the edge of the disk, to retain the disk stationary 'when a line is being drawn. The slides in the drawing-board areI actuated by handles.

North and south lines may be produced by moving the slide 39 the required distance, measured by the side scales, and east and west lines by moving the frame the required distance, measured by the scales on theend bars 42 42, the pen remaining stationary in either case, but one of the pens must be adjusted in the holder 36 to draw transversely to the rule. Circular lines may he produced by setting the pen the required distance from the center of the disk and rotating the disk, and broken lines by alternately raising and lowering the pen-shaft when the slide or frame is being moved. The rule may be graduated as desired, but preferably, from a division on each side of the longitudinal center of the rule, which is the ends of the apertures on each side of the slide 29 when the pen-attachment is locked by the stop in the slot 32 on the rule, and graduated each way from those points toward the opposite ends of the rule, permitting the reading of the scales on the rule from the ends of the apertures, otherwise, if the rule was graduated each way from the center, thereading of the scales would be somewhat obstructed by the blades of the pen.

To illustrate the operation of the instrument, take the following field notes of a survey and draw a plot thereto, to wit;

N. 20o E. 8. 66 chains S. E. 5.00 S. 10 E. 10.00 N

Place the drawing material on the slide 39, and secure it by placing a thin metal bar across the north and south ends, or by some attachment on the slide, adjust the frame so that the drawing may begin at the place desired on the drawing surface, note what divi sion of either of the scales 42 42, the central division of either of the verniers 45 45 coincides with, then rotate the disk until the 20o division of the northeast quadrant of the compass circle coincides with the central division of the vernier at the north point of the compass circle, move the pen-slide 29 toward the north end of the rule until the point of the pen, as shown by the vernier 47 on the slide, stands 8.66 chains from the center of the disk, with the index finger depress the pen-shaft 31 until the point of the pen comes in contact with the drawing surface, and while retaining it there, move the penslide toward the center of the rule until it is locked by the stop entering the groove 32 in the rule, which will produce the line AB, 8.66 chains in length, then reverse the disk until it locks and the line will be shown at its proper angle. Next so adjust the frame and its slide that theB end of the line is at the center of the disk and directly under the point of the pen, The side scales, or either of them, will show that the latitude of the line is 8.14 chains, and the end scales, or either of them, will show that its meridian distance is 2.96 chains. Note these facts in a conveniently arranged tablet. Next rotate the disk until the 70o division of the southeast quadrant of the compass circle coincides with the central division of the vernier at the south point, and proceed, as before, and draw lthe line BC. The scales will show that its latitude is 1.71 chains, its casting 4.70 chains, its meridian distance 7 .66 chains, and its double meridian distance 10.62 chains, which results note in the tablet, proceed in the same manner to draw the remaining sides of the field, and

from the data thus ascertained the area of the field may be computed by a simple calculation. Elevation and depression may be measured from given data according to geometrical formulas.

I claim:

l. In a drafting instrument, the combination with a polygonal shaped base mounted on legs, and comprising, a central horizontal circular plate, with a circular rim projection and a central cylindrical projection on its upper surface, with a central and circular vertical orifice through the cylindrical projection, ribs extending horizontally from the edge of the body of the plate and attaching to the sides of the base at their angles, the upper surface of the ribs and sides of the base lying in the same plane as the upper surface of the body of the plate two horizontal arms, oppositely placed and extended outward from the upper portion of the sides of the base, having a vertical rectangular oriice through each near the outer ends to receive the vertical supports, of a vertical support attached to each arm near its outer end, all of said supports being retained in said orifices by set-screws of a disk, centrally and rotatably mounted thereon, consisting, of a central horizontal circular plate, having a circular rim projection and a central cylindrical projection on its under surface, with a central shaft fixed therein and extending vertically downward and adapted to operate in the central orifice of thebase, the outer and kinner edges of the rim projection and periphery of the cylindrical projection coinciding with the similar projections of the base, horizontal ribs extending from the edge of the body of the plate and attaching to an outer circular rim, on the outer and upper surface of which is inscribed a compass circle, figured each way from 0O to 90O from the north and south points, the upper surface of the plate, ribs and outer rim lying in the same plane, the under surface of the projections lying in the same plane, but the under surface of the ribs slant upward and outward from the plate to the outer rim, of a rectangular rule, extending across, above and along the center of the horizontal plane of the disk, having inscribed on each side a scale of linear measurement graduated as desired, the ends adjustably attached to the upper ends of the vertical supports on the horizontal arms of the base, substantially as described. 2. In a drafting instrument, the combination with a base mounted on legs, having a central horizontal circular plate With a rim and cylindrical projections on its upperv surface, with a central circular vertical oriiice through the cylindrical projection, horizontal ribs extending from the body of the plate and attaching to the sides of the base, the 1 the upper surface of the sides, ribs and body of the plate lying in the same plane, two horizontal arms, oppositely placed and extended from the upper and outer portion of the sides of the base, of a vertical support attached to each arm near its outer end, of a disk, centrally and rotatably mounted thereon, consisting, of a central and horizontal circular plate having a rim projection and a cylindrical projection on its under surface, and a central shaft fixed therein extending downward and adapted to operate in the central orifice of the base, the periphery of the projections coinciding with the similar projections of the base, horizontal ribs extending from the outer edge of the body of the plate and attaching to the outer circular rim, on the upper and outer surface of which is inscribed a compass circle, graduated each way from 0O to 90 from the north and south points, the upper surface of the plate, ribs and rim lying in the same plane, the under surface of the ribs slant upward and outward from the plate to the rim, of a rectangular rule extending across, above and along the center of the horizontal plane of the disk, on each side of which is inscribed a scale of linear measurement, graduated as desired, the ends adjustably attached to the upper ends of the vertical supports on the horizontal arms of the base, of a drawing-board mounted on the upper surface of the disk, comprising areetangular frame, slidably adjusted by means of end bars, and a slide therein adjusted to move in and over the ends of the frame, substantially as set forth.

3. In a drafting instrument, the combination with a baseA mounted on legs, having a central horizontal circular plate with a rim and cylindrical projections on its upper surface, with a central circular vertical oriiice through the cylindrical projection, horizontal ribs extending from the body of the plate and attaching to the sides of the base, the upper surface of the sides, ribs and body of the plate lying in the'same plane, two horizontal arms, oppositely placed and extended from the upper and outer portion of the sides of the base, of a vertical support attached to each arm near its outer end, of a disk, centrally and rotatably mounted thereon, consisting, of a central and horizontal circular plate having a rim projection and a cylindrical projection on its under surface, and a central shaft fixed therein extending downward and adapted to operate in the central orifice of the base, the periphery of the projections coinciding with the similar projections of the base, horizontal ribs extending from the body of the plate and attaching to the outer circular rim, on the upper and outer surface of which is inscribed a compass circle, graduated each way from 0 to 90 from north and south points, the upper surface of the plate, ribs and rim lying in the same plane, the under surface of the ribs slanting upward and outward from the plate` of a drawing-board mounted on the upper surface of the disk, comprising, a rectangular frame slidably mounted on end bars, and a slide therein, adjusted to move in and over the ends of the frame, the upper surface of each side of the frame having a scale of linear measurement inscribed thereon, in divisions corresponding with the divisions of the rule", and end bars having inscribed on their upper surface a scale of linear measurement, the divisions corresponding with the divisions of the rule, verniers centrally located on each side of the slide and ends of the frame, substantially as set forth.

4. In a drafting instrument of the character described, the combination with a base mounted on legs, having, horizontal arms oppositely placed and extended from its outer sides, of two vertical supports attached to the arms near their outer ends, of a disk centrally and rotatably mounted thereon, having a compass circle inscribed thereon, figured each way from 0o to 90 from the north and south points, of a rectangular rule extending across, above and along the center of the horizontal plane of the disk, on each side of which is inscribed a scale of linear measurement, graduated as desired, the ends adjustably attached to the upper ends of the vertical supports, of a drawing-pen attachment, consisting, of a rectangular slide having an inner rectangular opening throughout, a rectangular aperture in each side extending to near its ends, the edges slanting outward, a vernier inscribed on the lower slant of each aperture, a device centrally mounted on the 'upper portion of the slide, its under surface elevated above the upper surface of the slide, an upward extension at each end and also a downward and longitudinal extension along the upper portion of the slide, the ends of the longitudinal extension slanting diagonally inward and outward, each downward extension having a vertical slot extending from its lower edge, a penholder adapted to operate therein, and each extended end having a shaft, its head projecting above the upper surface of the extension, operatively fixed in a circular vertical orifice extending down into said slot and attaching to the upper end of the pen-holder,the lower end of the holder having a vertical orifice adapted to receive the shaft of a drawing-pen, which is retained by set-screws, the upper portion of each shaft being encircled by a spiral spring, a stop cylindrical in shape'at the top and rectangular at the bottom, operatively inserted through a spiral spring and the central cross portion of the device, the rectangular end extending down through the upper portion of the slide into a transverse groove in the upper surface of the rule, a slide, actuating the stop, operating in 'an orifice in the upper rectangular portion of the stop, having its upper surface slanting from near one end toward the other, vertical posts at the ends, and a longitudinal slot, through the end not slanting, to receive a guide post fixed in the upper portion of the pen-slide, substantially as set forth.

5. In a drafting instrument, Iof the kind described, the combination, of a base having two horizontal arms, oppositely placed and extended from the outer sides of the base, of two vertical supports attached to the upper surface of the arms near their outer ends, of a disk centrally and rotatably mounted thereon, having a compass circle inscribed on the upper surface of its outer rim, figured each way from (l)O to 90 from the north and south points, a rectangular rule extending across,

above and along the center of the horizontal plane of the disk, graduated as desired on each side in scales of linear measurement, the ends adjustably attached to the upper ends of the vertical supports, of a drawing-pen attachment operating on the rule, comprising, a slide with an aperture on each side and a vernier on the lower slant of each aperture, a cross device centrally mounted on the upper portion of the slide, with extended ends, a vertical shaft operatively fixed in each extended end and extending down into a slot in the lower end of the downward extension and attaching to a pen-holder adapted to operate in said slot, and a stop with means of locking the attachment; of a vernier attachment on each arm of the base, and comprising, a vertical support, a hinged inner piece and a horizontal bar attached to its upper end, its inner surface being the arc of a circle of the same periphery as the outer edge of the disk, its upper surface lying in the same plane as the upper surface of the rim of the disk, with a vernier inscribed thereon, graduated each way from or to a central division, and ad- I justed contiguously against the edge of the disk by means of a spiral spring encircling a pin .fixed in the vertical support and operating through the hinged inner piece, and one of said vernier attachments having a stop attached to a lever, the lower end of which is attached to the end of a screw entering the outer side of the vertical support, the stop being adjusted to operate through an orifice in said support, thence through a spiral spring by which it is actuated and throughl an orifice in the horizontal vernier bar and enter an orifice in the edge of the disk, substantially as set forth.

6. In a drafting instrument, the combination With a base mounted on legs having tWo horizontal arms, oppositely placed and extended from the upper and outer portion of the sides of the base, of a vertical support attached to each arm near its outer end, of a disk centrally' and rotatably mounted thereon, havingl a compass circle inscribed on its outer rim, figured each Way from 0o to 90o from the north and south points, a rule graduated on both sides and adjustably attached to the vertical supports on the arms of the base over the face and along the center of the horizontal plane of the disk, a drawing-board, comprising, a rectangular frame slidably fixed to the upper surface of the disk provided With end'bars, the frame havinO a slide in its upper portion adjusted to oper,- ate transversely to the movement of the frame, with scales on the end bars and sides of the frame and verniers on the sides of the slide and ends of the frame, as means of adjusting the initial point of a line to the center of the compass circle and finding the latitude, departure, meridian and double meridian distance of a line, substantially as set forth.

7. In a drafting instrument, the combinationjvith a base mounted. on legs, having two horizontal arms oppositely placed and extended from the outer sides of the base of a vertical support attached to each arm near its oauter end, of a disk centrally and rotatably mounted thereon, having a compass circle inscribed on its outer rim, figured each Way from 0o to 90O from the north and south points, of a rule extending across, above and along the center ofthe horizontal plane of the disk, its ends adjustably attached to the upper ends of the vertical supports on the arms of the base, as means of determining the bearing of a line, substantially as set forth.

8. In a drafting instrument, the combination With a base mounted on legs, having two horizontal arms oppositely placed and extended from the outer sides of the base of a vertical support attached to each arm near its outer end, of a disk centrallr and rotatably mounted thereon, having a compass circle inscribed on the upper surface of itsY outer rim, figured each Way from 0O to 90o from the north and south points, of a graduated rule extending across, above and along the center of the horizontal plane of the disk, its ends attached to the upper ends of the vertical supports on the arms of the base, as means of determining the bearing of a line and measuring its length, substantiallyT as set forth.

9. In a drafting instrument, the combination with a base mounted on legs, having tivo horizontal arms oppositely placed and extended from the outer sides of the base of a vertical support attached to each arm near its outer end, of a disk centrally and rotatably mounted thereon Wiht a compass circle inscribed on the upper surface of its outer rim, figured each Way from 0O to 90o from the north and south points, a graduated rule extending across, above and along the center of the horizontal plane of the disk, its ends adjustably attached to the upper ends of the vertical supports on the arms of the base, of a rectangular frame and slide therein, slidably mounted on the upper surface of the disk provided with end bars, as means of ad justing the drawing surface to a fixed point on the rule as the initial point of a line to be drawn, substantially as set forth.

10. In a drafting instrument, the combination With a base mounted on legs, having two horizontal arms oppositely placed and extended from the outer sides of the base of a vertical support attached to each arm near its outer end, of a disk centrally and rotatably mounted thereon with a compass circle inscribed on the upper surface of its outer rim, figured each Way from 0o to 90 from the north and south points, of a graduated rule extending across, above and along the center of the horizontal plane of the disk, its ends adjustably attached to the upper ends of the vertical supports on the arms of the base, of a rectangular frame and slide therein, slidably mounted on the upper surface of the disk in end bars, of a drawing-pen attachment operating on the rule,- having means of attaching a pen thereto on each side of the rule and adjusting same to draw longitudinally or transversely thereto, as means of producing north and south, and east and West lines, Without adjusting their initial points to the center of a compass circle, substantially as set forth.

JOSEPH I-I. BLAIR. IVitnesses:

GEORGE T. LEE,` WALLACE J. DAVIS. 

